1. Field of the Invention
The invention relates to a communication system comprising a service switching point, a cordless terminal unit and a corded terminal unit.
2. Discussion of the Related Art
Such a communication system is known from DE 42 07 748 A1. It comprises a service switching point arranged as an ISDN private branch exchange to which a plurality of corded terminal units (telephones) are connected. Furthermore are connected to the service switching point base stations which make communication with cordless terminal units (cordless telephones) possible.
In such state-of-the-art communication systems it is possible for performance features such as call diversion or call forwarding to be activated or de-activated respectively, in the service switching point via the corded terminal units. A subscriber who has the disposal in his office, for example, of both a corded and a cordless terminal unit, may choose by which terminal unit he wishes to take incoming calls. When he is in his own office he will take calls by the usually more comfortable corded terminal unit which has many performance features and a better transmission quality. If he leaves his office and wishes to stay within reach, the subscriber will take along his terminal unit and set up a call diversion or call forwarding to his cordless terminal unit in the service switching point via the corded terminal unit, in order to be able to receive calls and communicate via this cordless terminal unit. After returning to his office, the subscriber again de-activates the call diversion or call forwarding. In the case of call diversion, incoming calls are directly diverted to the appropriate terminal unit by the service switching point. In the case of call forwarding, an incoming call is diverted only if the incoming call has not been taken by that particular subscriber in a given period of time.